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Fidd88

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Everything posted by Fidd88

  1. So, some good news now. I've finalised the design of the geodetic channel, and now know how the internal fittings can be made. Hope this week to start the process of getting the alloy extrusions made. Once they're in, I can check the actual dimensional accuracy of them, and if needbe, change the dimensions of the CNC'd parts from which moulds will be made prior to casting. Then the CNC'd parts can be made, and the mould-making can commence, from which wax patterns can be cast. After that they can be investment cast to produce the required parts in alloy. They can then be drilled with the requi
  2. Hi, I know the collector-ring itself is steel, ie the ring into which exhaust gases are collected from the exhaust manifolds. What's less clear, is if the shroud containing the ram-fed cooling air is an alloy or steel. Looking at the Brooklands Wellington, it certainly appears to be alloy, but still might be this steel. The corrosion in the Beaufighter ring pictured in thread, does suggest you're correct though. Next time I'm at Brooklands I'll place a magnet on it.
  3. Excellent post, it's great to see some colour pictures of them. I can't speak to the Beaufighter, but I'm fairly certain that on the Wellington, these Townsend Rings are a steel inner-collector-ring, taking the hot gasses, with an alloy shroud around it, which is fed with ram-air, thus cooling the exhaust gases before they're emitted, which reduced both flame-flare and noise. That said, your picture appears to show corrosion on them more consistant with very thin steel on the hotter external (radially) portion of the ring, which does cast into doubt, my assumption that they were alloy. Perhaps
  4. I also would highly recommend Fusion 360, even though some features that were previously available on the free hobby use version have recently been rescinded.
  5. I know! I spent some time talking to some of the chaps that did it, with a single hundred plus year old fly-press - and some determination! Talk about patience! You could have bottled my expression and sold for thruppence a time, once the full horror of building it thus sank into my conscious! Blimey, but that was a labour of love! My planned method looks positively Henry Fordesque compared with that - tiny movments at a time, and then drifting out the wood blocks afterwards. Crikey! The found a better frame 50 bulkhead (the one to which the trailing edge of the wing and aft end of the bomb b
  6. Cheers! The issue with the rolling-machine making the channel is not difficult about the cross-section, it's curving the geodetic during that's the complex bit. Hence my decision to extrude first and curve after. Which, incidentally, is how the missing geodetics on R for Robert at Brooklands, was made. I'm not a trained engineer at all, I worked in a motorcycle workshop years ago, rebuilding engines and servicing, so I've a little mechanical common-sense, and an O level in technical drawing from 40 years ago - indeed initial drawings for the turrets were pencil on paper at a drawing board
  7. Hi lads, I can't tell you how brilliant it has been to get some encouragement at this juncture in the project, as well as going through a divorce after 26 years - the Wellington seemed stymied at every turn, and has been really hard to keep up the enthusiasm for it in the face of difficulties with the riveting, and then insane quotes for things I'd assumed - my error - would not be overly dear. I really needed some encouragement to get past this point, as the difficulties expenses and technical problems were seemingly stacking-up faster than I could deal with 'em. So THANKS! Much apprecia
  8. Some better news. I've had some assistance from some of the other RC chaps who've suggested using CNC to make a small number of these fixings, and to use them to make a mould from which wax positives can be cast and attached on a suitable wax sprue. These can then be investment cast in alloy, in numbers, and machined/drilled/ground as required after the casting. Which puts it financially at least, back on track, and I get to learn some more skills! I've also had the offer of a loan of a small forge, which is both kind and hugely good for morale! I'll also be looking into a different form of ca
  9. Hi all, More news on the Wellington project - but not "good" news. I'd budgeted around £1000 to have the two types of solid internal fittings for the geodetic joints, as shewn in the film above, and found a company in China who were able to undertake the work. When the quote came back it was (for 13,000 fittings) over £17,000! Which is a complete show-stopper if I can't work around it. I'm currently investigating making the "butterfly" and "wishbone" joints by folding flat sheet cut to shape - which is a much cheaper proposition to have done, but may be problemtical in practice, and
  10. After a couple of days at the pc the two main joint-types for the alloy "basket" which forms the fuselage and wings of a Wellington have been drawn up to ensure I can get all the internal metal fittings made before the extrusion die tooling costs are paid.
  11. Not much news, but at last a little progress. I've got a mate to turn up a rivet-gun tool-tip for placing the 2mm diameter rivets, with a long enough reach to place them in the majority of the "ordinary" geodetic joints. All 16 rivets and 2 machine-screws with nuts per single joint! I haven't counted all the joints on the Wellington, but I expect to use well over 20,000 rivets on the whole airframe. I'm now redrawing all the joint fixtures and fittings, and the profile of the channel, as well as the inserts used to prevent the cross-section collapsing as it is curved. Have now decided to
  12. No problem. It always amazes me the breadth of knowledge in forums such as these, this was just one I happened to know a bit about. I can't remember what groceries I need - but this sort of stuff just seems to stick in my memory! Lord knows why... I forgot to mention that such gas-indicating paint was also applied to British field-guns, trucks, tanks and much else from the pre-war period until 1941, until it became evident we'd not all be clobbered with this muck at the outbreak of war. The "Keep Calm and Carry On!" poster is thought to have been designed to be read wearing a gas-mask. It
  13. Yes. It would have reacted to Mustard, turning from a yellowy zinc-chromate colour to pink in it's presence. It may also have been reactive to phosgene. As the German stance on using chemical weapons was unknown at the outbreak of war, but they'd been enthusiastic exponents of chemical warfare, in the Great War, the RAF was fully ready retaliate with mustard, were the Germans to use it first, and It was likely as much to indicate contamination from our own gas ordnance as enemy chemical attacks. Bombers carried circular indicators, around 9-12 inches in diameter, usually (but not exclusively)
  14. Hi all, I trust you're all keeping out of the path of this bloody virus? I was not surprised today when the British PM "cancelled Christmas" by doing away with a 5 day relaxation of the rules to enable us to get together. People just don't get it. We're in the fight of our lives against this damn bug, and being able to get together or go to the pub or whatever must come a very distant second to keeping the infected people requiring treatment below the point where our health services cannot cope - or else we'll cop for it like the Italians and New Yorkers did with mass-graves and much high
  15. Hi chaps. What with Covid, and it's effect on lots of companies, I'm struggling a bit to make progress at the moment. The rivet tool company I'm working with are having difficulties determining the tool-head to use to apply these very small (2mm diameter) pop-rivets. Until the tool-heads size is known, I can't do the CAD to finalise the extruded alloy profile or the sheer and gusset fittings, or the inserts needed to curve the extrusions. So, instead, I've been having a clear-out and reorganisation in the workshop to gain more space to the right of the bench, which I'll need for operating
  16. I'm unable to work these days - legacy of an old car-accident, so have decided to see if anyone wants one of these models, and is prepared to pay to have one built. To that end, I've put "commissioning one" onto Ebay to see if there's any interest. As they take 5-8 months to build and paint, and thousands of pounds to print all the parts to the required finish and dimensional accuracy, these are far from a cheap model to build. If I get a lot of interest I may look into getting parts injection-moulded, which would bring the per unit cost down, but raise the initial tooling costs. The item
  17. Thanks for posting those, quite comforting to know he's not perfect! Nice job capturing it correctly in the model!
  18. I'll try and answer this again. Lets say our fuselage was cylindrical, and there are no longerons to complicate matters. If we cut through the cylinder at 45 degrees, we end up with the cut face of the solid-cylinder being an ellipse. So, if we make a solid flat ellipse of the same size, and wind a soft-metal shape around that ellipse, when the resultant elliptical alloy channel is fitted at the correct 45 degree angle, the internal space will be circular again as viewed from the end of the cylinder. The same principle holds true if our cylinder tapers, only now the start-point of the cha
  19. Interesting geometry on those doors. I've never seen a picture of one with the doors open, but I'd have expected the fully-open door position to be the lowest point of the door to be inline with the hinge-line - where it couldn't exert any further force on your hand if it were trapped between the door and items on the outside of the vehicle. A "stop" is also usually fitted to prevent the door or hatch opening beyond that point. As an ex-"tankie" you tend to value little design features like this, as the number of ways you can lose/crush/cut-off fingers/feet and heads on any armoured-vehicle a
  20. Well I'm just back from the rivet-gun shop (more of a factory really) and the absolutely brilliant news is that the tool will fit on the gaps I have to work within on the current dimensions. They even gave me a tool nose to take home so I can draw it up in CAD and play around with it. That means a lot less work potentially! - And building stuff sooner! Loud cheers!
  21. It's nothing but compound curves! The formers are the shape of the path of the geodetic, not the fuselage as measured around say a bulkhead. But when installed, they will naturally create the shape of the fuselage. So one half of the formed shape covers the path as it goes upwards and backwards at 45 degrees from the longeron to which it is bolted, and then the other half describes the path from the midline backwards and downwards towards the longeron on the other side. The result should - If I've not bollocksed-up the theory, describe the shape of a geodetic passing from one side to the othe
  22. Such news at there is: I'm now at the phase of preparing to start metalwork, to fabricate the curved geodetic channels required to build the fuselage, wings and tail, and know how I'm going to go about it. The geodetic channel will be extruded in it's required cross-section, with a wall-thickness of 0.8mm (31 thou"). When it comes to bending it, a steel cable with a heavy weight on it will cause it to bend as the extruded tube is bent around a wooden former by being "wound" onto it, the steel cable causing it to conform thereto. Some 300 different formers being required just for the fusel
  23. No problem. Even if you don't use it on this model, a knowledge of how the components look like, and how the different types of rams operate. It might spark an idea for a project? I found the link to the film I made as I was assembling the turret rams, which shews the different parts.
  24. Honestly, pneumatics are a complete doddle. You've single-acting - one way - and double acting - two way. The first may likely of no use to you. Go to ocaire.com, find a suitable miniature (probably double-acting) ram, and buy some large syringes, and some pneumatic line (black 2mm PVC tube iirc), and start "playing". Connecting them up is simplicity itself, pvc put metal collet on tube, press tube into joint fitting, press collet back up tube and onto joint-fitting. Connect other end of tube to large syringe with non-sharp needle - (usually a pink plastic fitting with needle) and your done. I
  25. I'm glad to have been of help, Good luck with the bulldozer, I look forward to seeing it. How big is it? If the model is huge, you could look into pneumatic (air powered) rams for the bulldozer and digger-bucket on the back. Movement on a model is really striking if it's doable, and it's a lot of fun to do. Put on a diorama base, the pneumatic lines could be concealed in the base and just brought out to connect the syringes to start making things move,,,, Provided the model is big enough, the main rams for the dozer blade look emminently achievable. On my turrets I 3d printed a thin cover
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